<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>伪类</title>
    <style>
        span{
            display: none;
        }
        div:hover span{
            display: block;
        }
    </style>
</head>
<body>
<div>
<p>百度</p>
<span>糯米</span>
</div>
</body>
</html>